Although numerous teaching machines using a multiple choice worksheet have been proposed and some are in use, such devices suffer from certain deficiencies. Most multiple choice worksheet devices do not, for example, require the student to make a correct answer after an erroneous answer has first been made, nor do they permit the instructor to determine that the student has made one or more specific erroneous attempts prior to arriving at the correct response.
These and other features, including the ability of the instructor to prepare the worksheets using commonly available facilities, have become increasingly desirable in an era when the growing needs for training are accompanied by inadequate availability of teaching personnel. The need for an easily operable teaching machine capable of adaptation to a wide variety of training and teaching applications continues to be widely expressed, as is the need for flexibility in worksheet arrangement to allow adaptation to a wide range of uses from that in undeveloped countries to vocational training and from first year teaching to preparation for higher grade examinations.